# Does load factor affect roll rate?

To be clear I am referring to a given aircraft at a given weight, speed, attitude, etc everything else the same except one is at say 0.5g and the other at 2.5g will there be a difference in roll rate if both have the same aileron deflection etc.

From my reading I think the answer is no but I am looking for something definitive. The question arises because the typical nose low UA recovery is UNLOAD then roll and recover to the horizon. For what reason is the UNLOAD? Some have suggested that it is because you will get a better roll rate to get the wings level. This I am not sure about.

I believe the main reasons for unloading are that (1) you want to avoid asymmetrical 'g' loads and (2) when holding a large amount of elevator force the pilots ability to input up to maximum aileron deflection is limited.

So I would appreciate someone confirming or denying if there is an aerodynamic reason that roll rate is affected by load factor?

• There might be something here with gyroscopic physics, trying to pitch and roll at the same time. This could be tested. Rolling without pitching may allow the angular mass to accelerate in its plane undisturbed. Pitching and rolling together (rapidly) may have undesirable motion coupling. Jul 10, 2022 at 21:53
• Are you excluding cases where roll control is accomplished in full or in part with spoilers ("spoilerons") rather than ailerons? It makes a huge difference to the answer, whether or not these cases are excluded or included. "Unloading" the wing to well below 1G will greatly reduce the roll rate if roll control is accomplished mainly through spoilerons. Jul 13, 2022 at 2:10

## 3 Answers

Load factor effects roll rate if you are at a speed close to stall. Then the outer part of the rising wing will be at a higher AOA, possibly beyond stall. You may even roll off on that side as the rising wing stalls and the other doesn't, departing controlled flight.

The other reason not to do a rolling pull, is if you find yourself fast, a rolling pull can overstress the wings and result in structural failure. So I guess you could say that is a roll rate limiter too, if your wing falls off.

• Yes I agree with these thoughts. Still if the aircraft was slightly below Va would there be a difference in roll rate with a common aileron deflection at differing load factors? Apr 11, 2019 at 3:46
• I’d say no. As long as the rising wing where the aileron was located was below clmax, they would roll the same rate. Apr 11, 2019 at 11:24

One of the best reasons to unload before using your ailerons is to make sure you are not stalled. If you are, using ailerons could reverse and make you roll the opposite way.

Ailerons can be evil when used uncoordinated with rudder, yet very helpful rolling out of an inverted dive. The danger increases if the aircraft is yawing and near stall. So it is much safer to recover in 2 steps, unloading first.

All I have is this extract from the Embraer 190 SOP guiadance for the nose down upset recovery

"It is important to reduce load factor while attempting to roll to wings level because it increases the roll effectiveness while decreasing the asymmetric loads on the airplane."

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– Jamiec
Jul 10, 2022 at 17:42